JP2003511270A - Inlet closure bushings for plastic molding machines - Google Patents

Abstract

(57) Abstract: The inlet closing bushing (26) of the plastic molding machine has a threaded portion for sealing the interface between the bushing and the mold. When the threaded portion (56) of the bushing is received in the mold, the two surfaces contact the corresponding surfaces of the mold and the interface between the bushing and the mold is sealed. The body of the bushing houses the heating element (90) and other components and isolates them from plastic or contaminants that may leak into the molding machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION

The present invention relates generally to flow control of plastic material to a plastic molding machine, and more particularly to an inlet closure bushing that controls the flow rate of plastic to a plastic molding machine.

Molding of plastic is widely performed in various industries. One particular application is in the manufacture of automotive parts or components.

One of the immediate challenges is to properly control the flow rate of plastic material fed to the mold during the manufacturing process. Conventional approaches use a closed bushing to connect a source of plastic material to the mold. Conventional closure bushings have various drawbacks and problems. The main problem with the conventional method is that the lack of a suitable seal prevents the molten plastic material from exiting the molding machine and into the plastic damaging part of the machine. The interface between the closure bushing and the mold has been found to be the primary location for this unwanted leakage. Conventional mounting methods do not provide a sufficient seal to prevent plastic material from escaping from the interface between the inlet bushing and the mold.

Another problem with the conventional approach is that the various components associated with the closure bushing are exposed to contaminants including, but not limited to, molten plastic that leaks out of the desired location of the molding machine. Is to be done. For this reason, an operation stop time is required to stop the operation of the molding machine and repair or replace parts.
This is because one or more parts are exposed to the molten plastic material, which hinders or stops the operation of the molding machine.

There is a need for an improved device for delivering molten plastic to a mold. The present invention meets this need while avoiding the problems and drawbacks of the prior art described above.

[0006]

[Outline of the Invention]

The present invention, in a broad sense, relates to a molding machine for manufacturing articles from plastic materials.
The molding machine of the present invention has a mold with an inlet for receiving a plastic material. A source of plastic material is coupled to this mold via a bushing. The bushing includes a threaded portion that is received by the mold at the mold inlet such that when the bushing is mounted on the mold, the interface between the mold and the bushing is sealed.

According to a preferred embodiment, the bottom of the threaded part of the bushing is brought into contact with the corresponding surface of the mould, at the same time the bottom of the second part of the bushing is brought into contact with another part of the mould.
The simultaneous contact of the bottoms of the two surfaces effectively seals the interface between the mold and the bushing, preventing leakage of plastic material from the interface.

Another advantageous feature of the present invention is that it supports the heating element within the bushing body so that the heating element is isolated from the molten plastic material or other contaminants in the region of the bushing. Similarly, all electrical connections to the heating element are
The cover is isolated from the flow of plastic material, thereby significantly reducing downtime of the molding machine.

Various features and advantages of the present invention will become apparent to those of ordinary skill in the art by reading the following detailed description with reference to the accompanying drawings.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A molding machine 20 for manufacturing articles from plastic material has a mold 22. The type is
Preferably, it has a contoured surface that determines the shape of the part to be manufactured. A plastic source 24 supplies plastic material to the mold 22 via an inlet closing bushing 26. The plastic source 24 and mold 22 are conventional, except as noted below.

The bushing 26 has a body 30 which is preferably made of steel. One end 32 of the body 30 contacts and is received by the mold 22. The opposite end of the body 30 is provided with a cover 34, which facilitates coupling of the electrical connection means 36 with other components within the bushing, as described below.

The support structure 38 is fixed to a mounting plate 39, which is fixed to the body 30. The hydraulic device 40 operates to move the closure pin 42 radially with respect to the bushing 32. The preferred arrangement has a yoke 44 which allows the hydraulic device to move the pin 42 in the desired manner.

The pin 42 is preferably moved into or out of a flow channel 48 extending between an inlet 50 and an outlet 52. The closure pin 42 preferably moves, for example as indicated by arrow 53 in FIG. In the illustrated embodiment, the flow path 4
8 penetrates the main body 30 in the axial direction. The hydraulic device controls the flow rate of the plastic material into the mold inlet 54 by moving the pin 42 radially into or out of the channel 48.

The bushing 26 preferably has a threaded portion 56 that is received within the mold 22.
The threaded portion 56 preferably has a smaller outer diameter than the adjacent portion of the body 30.
The plurality of threads 58 are formed so that the bottom of the end face 60 of the threaded portion 56 contacts the corresponding surface of the mold 22. In the preferred embodiment, the adjacent portion of body 30 is
Surface 6 where the bottom of the end face 60 contacts the mold and at the same time the bottom contacts the corresponding surface of the mold 22.
Have two. The threads 58 are preferably abutted by the surfaces mentioned above at the same time,
The interface between 2 and the bushing 26 is effectively sealed. This configuration is superior to conventional methods in preventing leakage from the interface between the mold and bushing.

The various components of bushing 26, including body 30, cover 34 and mounting plate 39, are preferably formed of hardened steel. The cover 34 is
It is fixed to the main body 30 by the set screw 70. Similarly, mounting plate 39 is preferably secured to the body by setscrews 72,74. For example, a cover 34,
Set screws are preferably used so that the mounting plate 39 and the plate can be selectively removed from the body as needed, although other fastening schemes may be used.

As best shown in FIGS. 4 and 5, the bushing 80 allows the closure pin 42 to move relative to the body 30 to selectively close the flow of plastic material within the passageway 48. Is preferably supported. Bushing 80 preferably has a threaded portion 82 similar to threaded portion 56 of body 30. The threaded portion 82 is formed so that the bottom of the end face 86 contacts the corresponding surface of the main body 30. In the illustrated example, a separate bushing 88 for receiving the pin 42 is provided and the bushing 88 is provided.
Are received in the bushing 80. In another example, bushing portions 80, 88 are integrated into a single component. The bushing 80 prevents plastic from leaking around the edges of the closure pin 42.

Another advantageous feature of the invention is that all working parts affected by the leakage of the plastic are isolated from the flow of the plastic through the bushing.
A plurality of heating elements 90, which are preferably conventional heating rods, are supported within the body 30 and are isolated from the flow of plastic material. Further, the cover 34 isolates all electrical connection means to the heating element 90 so that leaking plastic material in the molding machine does not come into contact with any heating element or any electrical connection means. By isolating these components from potentially leaking plastic material, the inventive arrangements provide a robust system with less molding machine downtime or required repairs associated with conventional arrangements. It

The present invention is a significant improvement in the construction of connecting a source of plastic to the mold of a plastic molding machine. The structure of the present invention provides excellent sealing characteristics and durability.

The descriptions above are intended to be illustrative, not limiting. Various modifications and design changes of the illustrated and described embodiments will be obvious to those skilled in the art without necessarily departing from the spirit and scope of the invention. The scope of legal protection given to this invention can be determined by studying the appended claims.

[Brief description of drawings]

[Figure 1]   FIG. 1 is a schematic view of a molding machine designed according to the present invention.

[Fig. 2]   FIG. 2 is a perspective view of a bushing and mold designed according to the present invention.

[Figure 3]   FIG. 3 is a partial cross-sectional view taken along line 3-3 of FIG.

[Figure 4]   FIG. 4 is a partial cross-sectional view showing selected components of FIG.

[Figure 5]   FIG. 5 shows selected components of the apparatus of FIG.

[Figure 6]   FIG. 6 is a cross-sectional view taken along line 6-6 of FIG.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] October 18, 2001 (2001.10.18)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

Claims (19)

[Claims] 1. A molding machine for manufacturing articles from plastic material, comprising a mold having an inlet for receiving the plastic material, a source of the plastic material, and a bushing coupling the source to the mold. A molding machine in which the interface between the mold and the bushing is sealed because the threaded portion is received by the mold at the inlet. 2. The adjacent portion of the bushing has a larger dimension than the threaded portion of the bushing, and the adjacent portion of the bushing is in direct contact with the corresponding portion of the die when the threaded portion is fully received by the die. The molding machine according to claim 1. 3. The molding machine according to claim 2, wherein when the bottom of the end of the threaded portion contacts the corresponding surface of the mold, the bottom of the adjacent portion of the bushing simultaneously contacts the corresponding portion of the mold. 4. The molding machine according to claim 3, wherein the mold has a corresponding threaded portion that cooperates with the threaded portion of the bushing. 5. The molding machine of claim 1, wherein a plurality of heating elements are supported on the body portion of the bushing. 6. The molding machine of claim 5, wherein the heating element comprises a heating rod housed within the bushing body, the heating rod being isolated from the plastic material within the bushing. 7. The bushing has an inlet at a first end adjacent the source,
An outlet at a second end adjacent the inlet of the mould, and a cover element near the inlet of the bushing, the cover providing all electrical connections to the components supported by the bushing. The molding machine according to claim 1, which is covered. 8. The bushing is at least partially within the bushing, an inlet at a first end of the bushing adjacent to the source, an outlet at a second end adjacent to the mold inlet. 2. The molding machine of claim 1 having a closure pin that is supported to move to selectively stop the flow of plastic material from the inlet of the bushing to the outlet of the bushing to control the flow of plastic material to the mold. 9. The bushing inlet and outlet are at opposite ends of the axial passage through the bushing housing, and the closure pin is selectively movable radially with respect to the bushing housing to block the axial passage. 9. The molding of claim 8 wherein a portion of the closure pin extends radially outward from the bushing, the bushing having a plate portion secured to an outer surface of the bushing surrounding a portion of the pin extending from the bushing. Machine. 10. An apparatus for controlling the flow of plastic into a plastic mold having an inlet port, the body of the bushing having a first end having an inlet for receiving the plastic material,
A second end having an outlet for delivering plastic material to an inlet port of the mold, the body having a threaded portion near the second end and received near the inlet port of the mold. A device that controls the flow of plastic, where the threaded portion acts to seal the interface between the body and the mold. 11. A portion of the body adjacent to the threaded portion has a large outer dimension, as compared to an extension of the body having a threaded portion of the threaded portion, wherein the adjacent portion of the body directly contacts the corresponding surface of the mold. 11. The apparatus of claim 10 to seal the interface between the body and the mold. 12. The apparatus of claim 11, wherein the threaded portion, when the bottom of its end contacts the corresponding surface of the mold, the bottom of the adjacent portion of the bushing simultaneously contacts the corresponding portion of the mold. 13. The apparatus of claim 10, wherein the plurality of heating elements are supported to be isolated from the plastic material within the bushing. 14. A bushing has a cover element covering a first end inlet, a second end outlet, and near the bushing inlet all electrical connections to components supported by the bushing. The apparatus of claim 10 having: 15. A bushing has an inlet and an outlet at opposite ends of an axial passage through the body and a closure pin is selectively movable radially with respect to the body to a position blocking the axial passage. 15. The apparatus of claim 14, wherein a portion of the closure pin extends radially outward from the bushing, the bushing having a plate secured to an outer surface of the bushing surrounding a portion of the closure pin extending from the bushing. 16. A bushing for coupling a plastic source to a plastic molding machine, the inlet and outlet being at opposite ends of a passage and a plurality of heating elements supported therein to be isolated from the plastic material passing through the passage. A bushing comprising a housing having. 17. The bushing of claim 16 wherein the heating element is powered and has a cover near the inlet that covers all electrical connection means to the heating element. 18. A device for controlling the flow rate of plastic into a plastic mold, the inlet of a first end receiving the plastic material and the outlet of a second end feeding the plastic material into an inlet port of the mold. And a bushing body having a plurality of heating elements supported therein to be isolated from the plastic material. 19. The apparatus of claim 18, wherein the heating element is completely covered by the material of the body.